MOODLE_27_STABLE only: remove this file in your site if present: dataroot/temp/olson.txt remove this file in your site if present: dataroot/temp/timezone.txt disable network access, so http://download.moodle.org/timezone/ cannot be accessed go to Admin -> Location -> Update timezones press the continue button, so the local lib/timezone.txt will be loaded TEST: With debugging enabled, you should get one message like "cURL request for "http://download.moodle.org/timezone/" failed...". Perfect, that means you disabled network access ok. TEST: ignoring the previous warning, the load ends without any PHP notice/warning/error. TEST: The page shows this info: "2409 entries imported from YOUR_MOODLE_BASEDIR/lib/timezone.txt". 2409 is the important bit. And also that the load has happened from that directory. TEST: Run the phpunit tests, paying attention to any testmoodlelib.php result. Process should end with "xxx passes, 0 fails and 0 exceptions." (or, alternatively, if there are some tests failing, none of them are related to testmoodlelib.php and date/time functions). ANY MOODLE BRANCH, FROM 18_STABLE to 28_STABLE: POST-TEST (optional, must work if all the prev tests have worked): after rolling upstream (24h later at least), with network access enabled, load the timezones again, it should show the same number of timezones (2409) but loaded from http://download.moodle.org/timezone/